An aggressive approach to the treatment of testicular seminomas, utilizing super-voltage techniques, has resulted in 95 per cent survival for all stages. For the carcinoma group the sandwich technique has resulted in a sharper segregation of the Stage I and II cases with respect to survival with 100 per cent survival resulting in Stage I. Adjunctive chemotherapy may well be warranted in Stage II, where about one-third to one-half of the patients develop relapse or die. The value of analyzing such data by means of probability of disease-free survival is emphasized.